Posts Tagged: EV Tech Explained

The technical reasons Tesla would limit supercharging speed, and other practical charging considerations

Recently, a bit of a kerfuffle kicked up when a Tesla Model S owner noticed that the maximum charge rate for his car on the Supercharger network had suddenly been cut from 120 kW down to 90 kW, apparently the result of too many fast charge cycles. Tesla’s explanation was, essentially, that many things can… Read more »

VIDEO: Just how does an EV work, anyway?

Judging from the articles that appear in the mainstream press, there’s still a lot of confusion and ignorance about how EVs actually work. Anyone who’d like a little deeper understanding of the workings of an electric powertrain, without going to engineering school, would do well to watch “How does an Electric Car work?” Part of… Read more »

EV tech explained: What are the limiting factors of an EV’s regenerative braking force?

In many EVs, regenerative braking is limited by the manufacturer to a modest level, and usually offers little or no ability for the driver to adjust it (aside from the few cases in which regen is made proportional to the initial movement of the brake pedal). Is tepid regen braking the result of some sort… Read more »

EV tech explained: Why do EVs restrict the amount of battery capacity that can be used for driving?

All EVs that use lithium-ion batteries are designed so that their full capacity can’t be used in driving – a few kWh are always left over as a buffer. Sometimes you’ll find this figure in spec sheets, which might (for example) quote capacity as “60 kWh (55 usable)” or some such. What is the reason… Read more »

A closer look at wire bonding

Wire bonding technology – widely utilized in the microelectronics and power electronics industries since the 1970s – is finding its way into interesting new applications in the growing EV industry – in particular, battery connections. We’re quite certain that a few EVs are using wire-bonding technology for production battery pack connections, but Charged was unable… Read more »

A closer look at electrolytes in advanced batteries

The electrolytes in advanced batteries are based on incredibly complicated formulations. If you calculated all of the possible combinations of solvents, salts and additives while trying to find the optimal ratios for just one electrolyte formulation, it would add up to an extraordinary number of possibilities. Because it plays such a critical role in battery… Read more »

Tesla tweaks its battery chemistry: a closer look at silicon anode development

In mid-July, Tesla Motors made a trio of Model S update announcements. The new options included a 70 kWh rear-wheel-drive base model, an upgrade for the high-end battery pack from 85 to 90 kWh (providing about a 6% increase in range), and Ludicrous mode, which offers a 10% improvement in the car’s 0 to 60… Read more »

A closer look at torque ripple – minimizing its effects on electric machines

The Switched Reluctance Motor, or SRM, is often discussed as a prime choice for the next-generation EV traction motor. It is simple, robust, and arguably the least expensive of all motor types to manufacture. However, SRMs are notoriously difficult to control, and prone to emitting significant amounts of vibration and acoustic noise. The good news… Read more »

A closer look at how batteries fail

A lot of research has been done to improve lithium-ion battery safety, cycle life and power output over a range of high and low temperatures, yet understanding the fundamental processes and degradation mechanisms in Li-ion batteries remains a challenge. To understand the degradation processes of lithium-ion batteries, it is important to understand how they operate…. Read more »

A closer look at the semiconductor switch

In this article I’ll be giving an overview of that most important of power electronics components: the semiconductor switch. I’ll first address what a switch is, and then delve into some of the more important compromises and shortcomings that exist in real-world switches that engineers must contend with when designing chargers, motor controllers, DC-DC converters… Read more »